The present invention relates to a rotor, a method for producing a rotor, an asynchronous machine and a vehicle. The present invention relates, in particular, to a rotor for an asynchronous machine, a method for producing a rotor for an asynchronous machine, an synchronous machine, in particular for a drive of a vehicle, and a vehicle, in particular a passenger car and/or a hybrid vehicle.
Asynchronous machines are used in many technical applications, in particular when providing drive to vehicles and their components. Such machines are also referred to as three-phase asynchronous machines or three-phase induction machines. In such machines, a rotor and a stator interact with one another via rotational magnetic fields, wherein in the generator mode the rotor leads the stator rotational field, and in the motor mode the rotor lags the stator rotational field.
In the case of passive asynchronous machines, the rotor is constructed by a short-circuit rotor or cage rotor. Such a rotor is composed of a laminated core, in particular of an iron laminated core with grooves constructed therein, wherein the laminations are electrically insulated from one another. Rods are usually introduced into the grooves in the laminated core and electrically short-circuited by way of short circuit rings, which can be done by means of a casting process.
It is problematic that substitution of materials in order to improve the electrical conductance values, on the one hand, and increase the mechanical stability, on the other, cannot be carried out with known production methods, or can only be carried out with considerable additional expenditure in terms of material and costs.
The invention is based on the object of specifying a rotor for an asynchronous machine, which rotor makes the design and the operation of an asynchronous machine more reliable, without increasing expenditure during production. In addition, the invention is based on the object of specifying a corresponding production method for a rotor, an asynchronous machine and a vehicle and correspondingly developing said method.
The object on which the invention is based is achieved according to the invention with a rotor for an asynchronous machine, a method for producing a rotor for an asynchronous machine, an asynchronous machine so produced, and a vehicle with the asynchronous machine, in accordance with embodiments of the invention.
According to one aspect of the present invention, a rotor is provided for an asynchronous machine, comprising a laminated core and a short-circuit cage (also known as a “squirrel” cage) which is at least partially integrated into the laminated core, in which (i) the short-circuit cage is constructed with rods made with or from a first electrically conductive material and short-circuit rings made with or from a second electrically conductive material, (ii) a support ring is constructed on at least one of the short-circuit rings in mechanical contact therewith, (iii) a respective short-circuit ring and/or a respective support ring has a contour for forming the mechanical contact, and (iv) a respective mechanical contact is constructed as a press-fit for a positively locking and/or a frictionally locking connection. By way of the measures provided according to the invention and, in particular, by the construction of a respective mechanical contact via a contour in the manner of a press-fit on at least one of a respective short-circuit ring and a respective support ring, a short-circuit ring can be mechanically stabilized with simple mounting of a support ring on the respective short-circuit ring as an end ring with particularly simple measures and at the same time with a high level of reliability.
In one preferred development of the rotor according to the invention, the mechanical stabilization of a respective short-circuit ring is increased by a respective support ring in that a respective support ring is constructed as a structure which is positively locking and/or frictionally locking and, in particular, pressed on to the respective short-circuit ring. By virtue of these measures, the centrifugal loading can be applied to the support ring and compensated during the operation of the rotor in order to stabilize the respective short-circuit ring.
In another advantageous development of the rotor according to the invention, the underlying production process is simplified by virtue of the fact that a respective contour is constructed entirely or partially as a structure which is integral with the respective support ring and/or with the respective short-circuit ring.
As an alternative, a respective contour can, however, also be constructed entirely or partially as a structure which is added subsequently to the respective support ring and/or to the respective short-circuit ring.
In order to increase further the degree of mechanical coupling via the mechanical contact between the respective support ring and the respective short-circuit ring, it is possible, according to another advantageous embodiment of the rotor according to the invention, to provide that a respective contour is constructed with a surface profile, with one or more recesses and/or with one or more projections for forming and/or for assisting the mechanical contact.
A particularly high degree of mutual mechanical interaction and stabilization between a respective short-circuit ring and a respective support ring occurs, in particular, when a respective short-circuit ring and a respective support ring are constructed with contours which cooperate and/or are at least partially complementary to one another.
A particularly high level of mechanical stabilization of the rotor according to the invention also arises when a respective support ring is constructed entirely or partially on the outer circumference on the respective short-circuit ring and/or entirely or partially embedded in the respective short-circuit ring.
Since with respect to the support ring the electrical properties of the short-circuit ring are, depending on the positioning in relation to the short-circuit ring, not significant, the possibility is provided of a more wide-ranging selection of materials, in particular with respect to stabilizing the short-circuit ring with respect to large centrifugal forces, in particular in the case of untrue running.
Therefore, according to an alternative embodiment of the rotor according to the invention, a respective support ring is constructed with or from a material from the group of materials which comprises metallic materials, ceramic materials, plastics, composites, in particular with or from glass materials and/or carbon fiber materials, and combinations thereof.
Alternatively, a support ring can also be constructed with or from the same material as the respective short-circuit ring.
The stabilization of the short-circuit ring or rings in mechanical terms by the use of a support ring also permits use of material combinations with respect to the rods and/or the short-circuit rings, particularly taking into account the respective electrical conductivity and, if appropriate, without particular focus on the mechanical stability of the short-circuit ring because according to the invention the latter is stabilized mechanically by the support ring.
It is therefore, in particular, possible that (i) the rods are constructed in or with a cast and/or joined structure, (ii) one or more of the short-circuit rings are embodied as end rings, (iii) the first material has a higher electrical conductivity than the second material, (iv) the second material has a higher mechanical strength and/or stability than the first material, (v) the first material and/or the second material have/has a material from the group consisting of aluminum, copper, silver and combinations and alloys thereof, and/or (vi) the first material is or has copper or a copper alloy, and the second material is or has aluminum or an aluminum alloy.
According to another aspect of the present invention, a method for producing a rotor for an asynchronous machine is provided.
Such an asynchronous machine is constructed with a laminated core and at least one short-circuit cage which is partially integrated into the laminated core. According to the invention, in the production method, the short-circuit cage is constructed with (a) rods which are constructed with or from a first electrically conductive material, and (b) with short-circuit rings which are constructed with or from a second electrically conductive material. At least one of the short-circuit rings is constructed in mechanical contact therewith with a support ring. In this context, a respective short-circuit ring and/or a respective support ring is provided with a contour in order to form the mechanical contact, and a respective mechanical contact is constructed as a press-fit for a positively locking and/or a frictionally locking connection. As result, with the production method according to the invention, a support ring is constructed on at least one of the short-circuit rings and in mechanical contact therewith, and the mechanical contact is implemented via a contour on at least one of the respective short-circuit ring and the respective support ring, as a press-fit, a particularly high level of mechanical integrity of the produced rotor is obtained, specifically even in the case of high centrifugal loading and partial untrue running.
In one preferred development of the production method according to the invention, the mechanical integrity and durability of the produced rotor is increased by virtue of the fact that a respective support ring is constructed as a structure which is positively locking and/or frictionally locking and, in particular, pressed on to the respective short-circuit ring.
Particularly simple production occurs if a respective contour is entirely and/or partially constructed as a structure which is integral with the respective support ring and/or with the respective short-circuit ring.
As an alternative, it may also be advantageous if a respective contour is added entirely or partially as a subsequent structure to the respective support ring and/or to the respective short-circuit ring.
In addition, the mechanical interaction between the support ring and the short-circuit ring can be improved for the sake of increased mechanical stability in that, according to a further preferred embodiment of the method according to the invention, a respective contour is constructed with a surface profile, with one or more recesses and/or with one or more projections for forming or assisting the mechanical contact.
In addition, it may be advantageous if both the short-circuit ring and the support ring which interacts with the short-circuit ring are both constructed with a contour, in particular if a respective short-circuit ring and a respective support ring are constructed with contours which cooperate and/or are at least partially complementary to one another.
In one advantageous development of the production method according to the invention, in order to achieve a particularly high level of mechanical stability, a respective support ring is entirely or partially constructed on the outer circumference of the respective short-circuit ring and/or entirely or partially embedded in the respective short-circuit ring.
Material aspects can also be taken into account in order to increase the stability of the structure to be produced.
This can be done, for example, in that, according to one preferred embodiment of the production method, a respective support ring is constructed with or from a material from the group of materials consisting of metallic materials, alloys, ceramic materials, plastics, composites, in particular with or from glass materials and/or carbon fiber materials, and combinations thereof.
As an alternative to this, a support ring can also be constructed with or from the same material as the respective short-circuit ring.
According to further alternatives of the production method according to the invention, there may be provision that (i) the rods are constructed in or with a cast and/or joined structure, (ii) one or more of the short-circuit rings are embodied as end rings, (iii) a material with a higher electrical conductivity than the second material is used as the first material, (iv) a material with a higher mechanical strength and/or stability than the first material is used as the second material, (v) a material from the group consisting of aluminum, copper, silver and combinations and alloys thereof is used as the first material and/or as the second material and (vi) in particular, copper or a copper alloy is used as the first material, and aluminum or an aluminum alloy is used as the second material.
The method according to the invention is configured in a particularly economical way according to one advantageous development if a respective short-circuit ring is constructed by a casting process using a mold, and at the same time the mold has a complement of the contour of the short-circuit ring, and in this way when the short-circuit ring is cast it is also cast in an integral fashion with the contour.
The present invention also provides an asynchronous machine, in particular for the drive and/or as a generator of a vehicle. The asynchronous machine according to the invention has a rotor according to the invention and a stator.
In addition, the present invention provides a vehicle, in particular a passenger car, battery-operated electric vehicle and/or a hybrid vehicle. The vehicle comprises an asynchronous machine which is constructed according to the invention and which is constructed as part of a drive and/or of a generator of the vehicle.
The asynchronous machine according to the invention can also be used in any other devices as a drive and/or as a generator component, e.g. in working machines or machine tools, in particular in a circular saw, in pumps, e.g. water pumps, in hydraulic generators and wind-powered generators and the like.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.